package org.json;


/*
 * Copyright (c) 2002 JSON.org
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * The Software shall be used for Good, not Evil.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
import java.io.IOException;
import java.io.Serializable;
import java.io.Writer;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.lang.reflect.Method;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.TreeSet;


/**
 * A JSONObject is an unordered collection of name/value pairs. Its external
 * form is a string wrapped in curly braces with colons between the names and
 * values, and commas between the values and names. The internal form is an
 * object having
 * <code>get</code> and
 * <code>opt</code> methods for accessing the values by name, and
 * <code>put</code> methods for adding or replacing values by name. The values
 * can be any of these types:
 * <code>Boolean</code>,
 * <code>JSONArray</code>,
 * <code>JSONObject</code>,
 * <code>Number</code>,
 * <code>String</code>, or the
 * <code>JSONObject.NULL</code> object. A JSONObject constructor can be used to
 * convert an external form JSON text into an internal form whose values can be
 * retrieved with the
 * <code>get</code> and
 * <code>opt</code> methods, or to convert values into a JSON text using the
 * <code>put</code> and
 * <code>toString</code> methods. A
 * <code>get</code> method returns a value if one can be found, and throws an
 * exception if one cannot be found. An
 * <code>opt</code> method returns a default value instead of throwing an
 * exception, and so is useful for obtaining optional values. <p> The generic
 * <code>get()</code> and
 * <code>opt()</code> methods return an object, which you can cast or query for
 * type. There are also typed
 * <code>get</code> and
 * <code>opt</code> methods that do type checking and type coercion for you. <p>
 * The
 * <code>put</code> methods adds values to an object. For example,
 * <pre>
 *     myString = new JSONObject().put("JSON", "Hello, World!").toString();</pre>
 * produces the string
 * <code>{"JSON": "Hello, World"}</code>. <p> The texts produced by the
 * <code>toString</code> methods strictly conform to the JSON syntax rules. The
 * constructors are more forgiving in the texts they will accept: <ul> <li>An
 * extra
 * <code>,</code>&nbsp;<small>(comma)</small> may appear just before the closing
 * brace.</li> <li>Strings may be quoted with
 * <code>'</code>&nbsp;<small>(single quote)</small>.</li> <li>Strings do not
 * need to be quoted at all if they do not begin with a quote or single quote,
 * and if they do not contain leading or trailing spaces, and if they do not
 * contain any of these characters:
 * <code>{ } [ ] / \ : , = ; #</code> and if they do not look like numbers and
 * if they are not the reserved words
 * <code>true</code>,
 * <code>false</code>, or
 * <code>null</code>.</li> <li>Keys can be followed by
 * <code>=</code> or
 * <code>=></code> as well as by
 * <code>:</code>.</li> <li>Values can be followed by
 * <code>;</code> <small>(semicolon)</small> as well as by
 * <code>,</code> <small>(comma)</small>.</li> <li>Numbers may have the
 * <code>0-</code> <small>(octal)</small> or
 * <code>0x-</code> <small>(hex)</small> prefix.</li> </ul>
 *
 * @author JSON.org
 * @version 2009-03-06
 */
public class JSONObject implements Serializable {

    /**
     * Default serial version uid.
     */
    private static final long serialVersionUID = 1L;

    /**
     * JSONObject.NULL is equivalent to the value that JavaScript calls null,
     * whilst Java's null is equivalent to the value that JavaScript calls
     * undefined.
     */
    private static final class Null {

        /**
         * There is only intended to be a single instance of the NULL object, so
         * the clone method returns itself.
         *
         * @return NULL.
         */
        protected final Object clone() {
            return this;
        }

        /**
         * A Null object is equal to the null value and to itself.
         *
         * @param object An object to test for nullness.
         * @return true if the object parameter is the JSONObject.NULL object or
         * null.
         */
        public boolean equals(Object object) {
            return object == null || object == this;
        }

        /**
         * Get the "null" string value.
         *
         * @return The string "null".
         */
        public String toString() {
            return "null";
        }
    }

    /**
     * The map where the JSONObject's properties are kept.
     */
    private Map map;

    /**
     * It is sometimes more convenient and less ambiguous to have a
     * <code>NULL</code> object than to use Java's
     * <code>null</code> value.
     * <code>JSONObject.NULL.equals(null)</code> returns
     * <code>true</code>.
     * <code>JSONObject.NULL.toString()</code> returns
     * <code>"null"</code>.
     */
    public static final Object NULL = new Null();

    /**
     * Construct an empty JSONObject.
     */
    public JSONObject() {
        this.map = new HashMap();
    }

    /**
     * Construct a JSONObject from a subset of another JSONObject. An array of
     * strings is used to identify the keys that should be copied. Missing keys
     * are ignored.
     *
     * @param jo A JSONObject.
     * @param names An array of strings.
     * @exception IllegalArgumentException if a value is a non-finite number 
     * or if a name is duplicated.
     */
    public JSONObject(JSONObject jo, String[] names) {
        this();
        for (int i = 0; i < names.length; i += 1) {
            putOnce(names[i], jo.opt(names[i]));
        }
    }

    /**
     * Construct a JSONObject from a JSONTokener.
     *
     * @param x A JSONTokener object containing the source string.
     * @throws JSONException If there is a syntax error in the source string or
     * a duplicated key.
     */
    public JSONObject(JSONTokener x) throws JSONException {
        this();
        char c;
        String key;

        if (x.nextClean() != '{') {
            throw x.syntaxError("A JSONObject text must begin with '{'");
        }
        for (;;) {
            c = x.nextClean();
            switch (c) {
            case 0:
                throw x.syntaxError("A JSONObject text must end with '}'");

            case '}':
                return;

            default:
                x.back();
                key = x.nextValue().toString();
            }

            /*
             * The key is followed by ':'. We will also tolerate '=' or '=>'.
             */

            c = x.nextClean();
            if (c == '=') {
                if (x.next() != '>') {
                    x.back();
                }
            } else if (c != ':') {
                throw x.syntaxError("Expected a ':' after a key");
            }
            putOnce(key, x.nextValue());

            /*
             * Pairs are separated by ','. We will also tolerate ';'.
             */

            switch (x.nextClean()) {
            case ';':
            case ',':
                if (x.nextClean() == '}') {
                    return;
                }
                x.back();
                break;

            case '}':
                return;

            default:
                throw x.syntaxError("Expected a ',' or '}'");
            }
        }
    }

    /**
     * Construct a JSONObject from a Map.
     *
     * @param map A map object that can be used to initialize the contents of
     * the JSONObject.
     */
    public JSONObject(Map map) {
        this.map = (map == null) ? new HashMap() : map;
    }

    /**
     * Construct a JSONObject from a Map.
     *
     * Note: Use this constructor when the map contains <key,bean>.
     *
     * @param map - A map with Key-Bean data.
     * @param includeSuperClass - Tell whether to include the super class
     * properties.
     */
    public JSONObject(Map map, boolean includeSuperClass) {
        this.map = new HashMap();
        if (map != null) {
            Iterator i = map.entrySet().iterator();

            while (i.hasNext()) {
                Map.Entry e = (Map.Entry) i.next();

                if (isStandardProperty(e.getValue().getClass())) {
                    this.map.put(e.getKey(), e.getValue());
                } else {
                    this.map.put(e.getKey(), new JSONObject(e.getValue(), includeSuperClass));
                }
            }
        }
    }

    /**
     * Construct a JSONObject from an Object using bean getters. It reflects on
     * all of the public methods of the object. For each of the methods with no
     * parameters and a name starting with
     * <code>"get"</code> or
     * <code>"is"</code> followed by an uppercase letter, the method is invoked,
     * and a key and the value returned from the getter method are put into the
     * new JSONObject.
     *
     * The key is formed by removing the
     * <code>"get"</code> or
     * <code>"is"</code> prefix. If the second remaining character is not upper
     * case, then the first character is converted to lower case.
     *
     * For example, if an object has a method named
     * <code>"getName"</code>, and if the result of calling
     * <code>object.getName()</code> is
     * <code>"Larry Fine"</code>, then the JSONObject will contain
     * <code>"name": "Larry Fine"</code>.
     *
     * @param bean An object that has getter methods that should be used to make
     * a JSONObject.
     */
    public JSONObject(Object bean) {
        this();
        populateInternalMap(bean, false);
    }

    /**
     * Construct a JSONObject from an Object using bean getters. It reflects on
     * all of the public methods of the object. For each of the methods with no
     * parameters and a name starting with
     * <code>"get"</code> or
     * <code>"is"</code> followed by an uppercase letter, the method is invoked,
     * and a key and the value returned from the getter method are put into the
     * new JSONObject.
     *
     * The key is formed by removing the
     * <code>"get"</code> or
     * <code>"is"</code> prefix. If the second remaining character is not upper
     * case, then the first character is converted to lower case.
     *
     * @param bean An object that has getter methods that should be used to make
     * a JSONObject.
     * @param includeSuperClass If true, include the super class properties.
     */
    public JSONObject(Object bean, boolean includeSuperClass) {
        this();
        populateInternalMap(bean, includeSuperClass);
    }

    private void populateInternalMap(Object bean, boolean includeSuperClass) {
        Class klass = bean.getClass();

        /*
         * If klass.getSuperClass is System class then force includeSuperClass
         * to false.
         */

        if (klass.getClassLoader() == null) {
            includeSuperClass = false;
        }

        Method[] methods = (includeSuperClass) ? klass.getMethods() : klass.getDeclaredMethods();

        for (int i = 0; i < methods.length; i += 1) {
            try {
                Method method = methods[i];

                if (Modifier.isPublic(method.getModifiers())) {
                    String name = method.getName();
                    String key = "";

                    if (name.startsWith("get")) {
                        key = name.substring(3);
                    } else if (name.startsWith("is")) {
                        key = name.substring(2);
                    }
                    if (key.length() > 0 && Character.isUpperCase(key.charAt(0)) && method.getParameterTypes().length == 0) {
                        if (key.length() == 1) {
                            key = key.toLowerCase();
                        } else if (!Character.isUpperCase(key.charAt(1))) {
                            key = key.substring(0, 1).toLowerCase() + key.substring(1);
                        }

                        Object result = method.invoke(bean, (Object[]) null);

                        if (result == null) {
                            map.put(key, NULL);
                        } else if (result.getClass().isArray()) {
                            map.put(key, new JSONArray(result, includeSuperClass));
                        } else if (result instanceof Collection) { // List or Set
                            map.put(key, new JSONArray((Collection) result, includeSuperClass));
                        } else if (result instanceof Map) {
                            map.put(key, new JSONObject((Map) result, includeSuperClass));
                        } else if (isStandardProperty(result.getClass())) { // Primitives, String and Wrapper
                            map.put(key, result);
                        } else {
                            if (result.getClass().getPackage().getName().startsWith("java") || result.getClass().getClassLoader() == null) {
                                map.put(key, result.toString());
                            } else { // User defined Objects
                                map.put(key, new JSONObject(result, includeSuperClass));
                            }
                        }
                    }
                }
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
        }
    }

    static boolean isStandardProperty(Class clazz) {
        return clazz.isPrimitive() || clazz.isAssignableFrom(Byte.class) || clazz.isAssignableFrom(Short.class)
            || clazz.isAssignableFrom(Integer.class) || clazz.isAssignableFrom(Long.class) || clazz.isAssignableFrom(Float.class)
            || clazz.isAssignableFrom(Double.class) || clazz.isAssignableFrom(Character.class) || clazz.isAssignableFrom(String.class)
            || clazz.isAssignableFrom(Boolean.class);
    }

    /**
     * Construct a JSONObject from an Object, using reflection to find the
     * public members. The resulting JSONObject's keys will be the strings from
     * the names array, and the values will be the field values associated with
     * those keys in the object. If a key is not found or not visible, then it
     * will not be copied into the new JSONObject.
     *
     * @param object An object that has fields that should be used to make a
     * JSONObject.
     * @param names An array of strings, the names of the fields to be obtained
     * from the object.
     */
    public JSONObject(Object object, String names[]) {
        this();
        Class c = object.getClass();

        for (int i = 0; i < names.length; i += 1) {
            String name = names[i];

            try {
                putOpt(name, c.getField(name).get(object));
            } catch (Exception e) {/*
                 * forget about it
                 */}
        }
    }

    /**
     * Construct a JSONObject from a source JSON text string. This is the most
     * commonly used JSONObject constructor.
     *
     * @param source A string beginning with
     * <code>{</code>&nbsp;<small>(left brace)</small> and ending with
     * <code>}</code>&nbsp;<small>(right brace)</small>.
     * @exception JSONException If there is a syntax error in the source string
     * or a duplicated key.
     */
    public JSONObject(String source) throws JSONException {
        this(new JSONTokener(source));
    }

    /**
     * Accumulate values under a key. It is similar to the put method except
     * that if there is already an object stored under the key then a JSONArray
     * is stored under the key to hold all of the accumulated values. If there
     * is already a JSONArray, then the new value is appended to it. In
     * contrast, the put method replaces the previous value.
     *
     * @param key A key string.
     * @param value An object to be accumulated under the key.
     * @return this.
     * @throws JSONException If the value is an invalid number or if the key is
     * null.
     */
    public JSONObject accumulate(String key, Object value)
        throws JSONException {
        testValidity(value);
        Object o = opt(key);

        if (o == null) {
            put(key, value instanceof JSONArray ? new JSONArray().put(value) : value);
        } else if (o instanceof JSONArray) {
            ((JSONArray) o).put(value);
        } else {
            put(key, new JSONArray().put(o).put(value));
        }
        return this;
    }

    /**
     * Append values to the array under a key. If the key does not exist in the
     * JSONObject, then the key is put in the JSONObject with its value being a
     * JSONArray containing the value parameter. If the key was already
     * associated with a JSONArray, then the value parameter is appended to it.
     *
     * @param key A key string.
     * @param value An object to be accumulated under the key.
     * @return this.
     * @throws JSONException If the key is null or if the current value
     * associated with the key is not a JSONArray.
     */
    public JSONObject append(String key, Object value)
        throws JSONException {
        testValidity(value);
        Object o = opt(key);

        if (o == null) {
            put(key, new JSONArray().put(value));
        } else if (o instanceof JSONArray) {
            put(key, ((JSONArray) o).put(value));
        } else {
            throw new JSONException("JSONObject[" + key + "] is not a JSONArray.");
        }
        return this;
    }

    /**
     * Produce a string from a double. The string "null" will be returned if the
     * number is not finite.
     *
     * @param d A double.
     * @return A String.
     */
    static public String doubleToString(double d) {
        if (Double.isInfinite(d) || Double.isNaN(d)) {
            return "null";
        }

        // Shave off trailing zeros and decimal point, if possible.

        String s = Double.toString(d);

        if (s.indexOf('.') > 0 && s.indexOf('e') < 0 && s.indexOf('E') < 0) {
            while (s.endsWith("0")) {
                s = s.substring(0, s.length() - 1);
            }
            if (s.endsWith(".")) {
                s = s.substring(0, s.length() - 1);
            }
        }
        return s;
    }

    /**
     * Get the value object associated with a key.
     *
     * @param key A key string.
     * @return The object associated with the key.
     * @throws JSONException if the key is not found.
     */
    public Object get(String key) throws JSONException {
        Object o = opt(key);

        if (o == null) {
            throw new JSONException("JSONObject[" + quote(key) + "] not found.");
        }
        return o;
    }

    /**
     * Get the boolean value associated with a key.
     *
     * @param key A key string.
     * @return The truth.
     * @throws JSONException if the value is not a Boolean or the String "true"
     * or "false".
     */
    public boolean getBoolean(String key) throws JSONException {
        Object o = get(key);

        if (o.equals(Boolean.FALSE) || (o instanceof String && ((String) o).equalsIgnoreCase("false"))) {
            return false;
        } else if (o.equals(Boolean.TRUE) || (o instanceof String && ((String) o).equalsIgnoreCase("true"))) {
            return true;
        }
        throw new JSONException("JSONObject[" + quote(key) + "] is not a Boolean.");
    }

    /**
     * Get the double value associated with a key.
     *
     * @param key A key string.
     * @return The numeric value.
     * @throws JSONException if the key is not found or if the value is not a
     * Number object and cannot be converted to a number.
     */
    public double getDouble(String key) throws JSONException {
        Object o = get(key);

        try {
            return o instanceof Number ? ((Number) o).doubleValue() : Double.valueOf((String) o).doubleValue();
        } catch (Exception e) {
            throw new JSONException("JSONObject[" + quote(key) + "] is not a number.");
        }
    }

    /**
     * Get the int value associated with a key. If the number value is too large
     * for an int, it will be clipped.
     *
     * @param key A key string.
     * @return The integer value.
     * @throws JSONException if the key is not found or if the value cannot be
     * converted to an integer.
     */
    public int getInt(String key) throws JSONException {
        Object o = get(key);

        return o instanceof Number ? ((Number) o).intValue() : (int) getDouble(key);
    }

    /**
     * Get the JSONArray value associated with a key.
     *
     * @param key A key string.
     * @return A JSONArray which is the value.
     * @throws JSONException if the key is not found or if the value is not a
     * JSONArray.
     */
    public JSONArray getJSONArray(String key) throws JSONException {
        Object o = get(key);

        if (o instanceof JSONArray) {
            return (JSONArray) o;
        }
        throw new JSONException("JSONObject[" + quote(key) + "] is not a JSONArray.");
    }

    /**
     * Get the JSONObject value associated with a key.
     *
     * @param key A key string.
     * @return A JSONObject which is the value.
     * @throws JSONException if the key is not found or if the value is not a
     * JSONObject.
     */
    public JSONObject getJSONObject(String key) throws JSONException {
        Object o = get(key);

        if (o instanceof JSONObject) {
            return (JSONObject) o;
        }
        throw new JSONException("JSONObject[" + quote(key) + "] is not a JSONObject.");
    }

    /**
     * Get the long value associated with a key. If the number value is too long
     * for a long, it will be clipped.
     *
     * @param key A key string.
     * @return The long value.
     * @throws JSONException if the key is not found or if the value cannot be
     * converted to a long.
     */
    public long getLong(String key) throws JSONException {
        Object o = get(key);

        return o instanceof Number ? ((Number) o).longValue() : (long) getDouble(key);
    }

    /**
     * Get an array of field names from a JSONObject.
     *
     * @return An array of field names, or null if there are no names.
     */
    public static String[] getNames(JSONObject jo) {
        int length = jo.length();

        if (length == 0) {
            return null;
        }
        Iterator i = jo.keys();
        String[] names = new String[length];
        int j = 0;

        while (i.hasNext()) {
            names[j] = (String) i.next();
            j += 1;
        }
        return names;
    }

    /**
     * Get an array of field names from an Object.
     *
     * @return An array of field names, or null if there are no names.
     */
    public static String[] getNames(Object object) {
        if (object == null) {
            return null;
        }
        Class klass = object.getClass();
        Field[] fields = klass.getFields();
        int length = fields.length;

        if (length == 0) {
            return null;
        }
        String[] names = new String[length];

        for (int i = 0; i < length; i += 1) {
            names[i] = fields[i].getName();
        }
        return names;
    }

    /**
     * Get the string associated with a key.
     *
     * @param key A key string.
     * @return A string which is the value.
     * @throws JSONException if the key is not found.
     */
    public String getString(String key) throws JSONException {
        return get(key).toString();
    }

    /**
     * Determine if the JSONObject contains a specific key.
     *
     * @param key A key string.
     * @return true if the key exists in the JSONObject.
     */
    public boolean has(String key) {
        return this.map.containsKey(key);
    }

    /**
     * Determine if the value associated with the key is null or if there is no
     * value.
     *
     * @param key A key string.
     * @return true if there is no value associated with the key or if the value
     * is the JSONObject.NULL object.
     */
    public boolean isNull(String key) {
        return JSONObject.NULL.equals(opt(key));
    }

    /**
     * Get an enumeration of the keys of the JSONObject.
     *
     * @return An iterator of the keys.
     */
    public Iterator keys() {
        return this.map.keySet().iterator();
    }

    /**
     * Get the number of keys stored in the JSONObject.
     *
     * @return The number of keys in the JSONObject.
     */
    public int length() {
        return this.map.size();
    }

    /**
     * Produce a JSONArray containing the names of the elements of this
     * JSONObject.
     *
     * @return A JSONArray containing the key strings, or null if the JSONObject
     * is empty.
     */
    public JSONArray names() {
        JSONArray ja = new JSONArray();
        Iterator keys = keys();

        while (keys.hasNext()) {
            ja.put(keys.next());
        }
        return ja.length() == 0 ? null : ja;
    }

    /**
     * Produce a string from a Number.
     *
     * @param n A Number
     * @return A String.
     * @throws JSONException If n is a non-finite number.
     */
    static public String numberToString(Number n)
        throws JSONException {
        if (n == null) {
            throw new JSONException("Null pointer");
        }
        testValidity(n);

        // Shave off trailing zeros and decimal point, if possible.

        String s = n.toString();

        if (s.indexOf('.') > 0 && s.indexOf('e') < 0 && s.indexOf('E') < 0) {
            while (s.endsWith("0")) {
                s = s.substring(0, s.length() - 1);
            }
            if (s.endsWith(".")) {
                s = s.substring(0, s.length() - 1);
            }
        }
        return s;
    }

    /**
     * Get an optional value associated with a key.
     *
     * @param key A key string.
     * @return An object which is the value, or null if there is no value.
     */
    public Object opt(String key) {
        return key == null ? null : this.map.get(key);
    }

    /**
     * Get an optional boolean associated with a key. It returns false if there
     * is no such key, or if the value is not Boolean.TRUE or the String "true".
     *
     * @param key A key string.
     * @return The truth.
     */
    public boolean optBoolean(String key) {
        return optBoolean(key, false);
    }

    /**
     * Get an optional boolean associated with a key. It returns the
     * defaultValue if there is no such key, or if it is not a Boolean or the
     * String "true" or "false" (case insensitive).
     *
     * @param key A key string.
     * @param defaultValue The default.
     * @return The truth.
     */
    public boolean optBoolean(String key, boolean defaultValue) {
        try {
            return getBoolean(key);
        } catch (Exception e) {
            return defaultValue;
        }
    }

    /**
     * Get an optional double associated with a key, or NaN if there is no such
     * key or if its value is not a number. If the value is a string, an attempt
     * will be made to evaluate it as a number.
     *
     * @param key A string which is the key.
     * @return An object which is the value.
     */
    public double optDouble(String key) {
        return optDouble(key, Double.NaN);
    }

    /**
     * Get an optional double associated with a key, or the defaultValue if
     * there is no such key or if its value is not a number. If the value is a
     * string, an attempt will be made to evaluate it as a number.
     *
     * @param key A key string.
     * @param defaultValue The default.
     * @return An object which is the value.
     */
    public double optDouble(String key, double defaultValue) {
        try {
            Object o = opt(key);

            return o instanceof Number ? ((Number) o).doubleValue() : new Double((String) o).doubleValue();
        } catch (Exception e) {
            return defaultValue;
        }
    }

    /**
     * Get an optional int value associated with a key, or zero if there is no
     * such key or if the value is not a number. If the value is a string, an
     * attempt will be made to evaluate it as a number.
     *
     * @param key A key string.
     * @return An object which is the value.
     */
    public int optInt(String key) {
        return optInt(key, 0);
    }

    /**
     * Get an optional int value associated with a key, or the default if there
     * is no such key or if the value is not a number. If the value is a string,
     * an attempt will be made to evaluate it as a number.
     *
     * @param key A key string.
     * @param defaultValue The default.
     * @return An object which is the value.
     */
    public int optInt(String key, int defaultValue) {
        try {
            return getInt(key);
        } catch (Exception e) {
            return defaultValue;
        }
    }

    /**
     * Get an optional JSONArray associated with a key. It returns null if there
     * is no such key, or if its value is not a JSONArray.
     *
     * @param key A key string.
     * @return A JSONArray which is the value.
     */
    public JSONArray optJSONArray(String key) {
        Object o = opt(key);

        return o instanceof JSONArray ? (JSONArray) o : null;
    }

    /**
     * Get an optional JSONObject associated with a key. It returns null if
     * there is no such key, or if its value is not a JSONObject.
     *
     * @param key A key string.
     * @return A JSONObject which is the value.
     */
    public JSONObject optJSONObject(String key) {
        Object o = opt(key);

        return o instanceof JSONObject ? (JSONObject) o : null;
    }

    /**
     * Get an optional long value associated with a key, or zero if there is no
     * such key or if the value is not a number. If the value is a string, an
     * attempt will be made to evaluate it as a number.
     *
     * @param key A key string.
     * @return An object which is the value.
     */
    public long optLong(String key) {
        return optLong(key, 0);
    }

    /**
     * Get an optional long value associated with a key, or the default if there
     * is no such key or if the value is not a number. If the value is a string,
     * an attempt will be made to evaluate it as a number.
     *
     * @param key A key string.
     * @param defaultValue The default.
     * @return An object which is the value.
     */
    public long optLong(String key, long defaultValue) {
        try {
            return getLong(key);
        } catch (Exception e) {
            return defaultValue;
        }
    }

    /**
     * Get an optional string associated with a key. It returns an empty string
     * if there is no such key. If the value is not a string and is not null,
     * then it is coverted to a string.
     *
     * @param key A key string.
     * @return A string which is the value.
     */
    public String optString(String key) {
        return optString(key, "");
    }

    /**
     * Get an optional string associated with a key. It returns the defaultValue
     * if there is no such key.
     *
     * @param key A key string.
     * @param defaultValue The default.
     * @return A string which is the value.
     */
    public String optString(String key, String defaultValue) {
        Object o = opt(key);

        return o != null ? o.toString() : defaultValue;
    }

    /**
     * Put a key/value pair in the JSONObject, where the value will be a
     * JSONArray which is produced from a Collection.
     *
     * @param key A key string.
     * @param value A Collection value.
     * @return this.
     */
    public JSONObject put(String key, Collection value) {
        put(key, new JSONArray(value));
        return this;
    }

    /**
     * Put a key/boolean pair in the JSONObject.
     *
     * @param key A key string.
     * @param value A boolean which is the value.
     * @return this.
     */
    public JSONObject put(String key, boolean value) {
        put(key, value ? Boolean.TRUE : Boolean.FALSE);
        return this;
    }

    /**
     * Put a key/double pair in the JSONObject.
     *
     * @param key A key string.
     * @param value A double which is the value.
     * @return this.
     */
    public JSONObject put(String key, double value) {
        put(key, new Double(value));
        return this;
    }

    /**
     * Put a key/int pair in the JSONObject.
     *
     * @param key A key string.
     * @param value An int which is the value.
     * @return this.
     */
    public JSONObject put(String key, int value) {
        put(key, new Integer(value));
        return this;
    }

    /**
     * Put a key/long pair in the JSONObject.
     *
     * @param key A key string.
     * @param value A long which is the value.
     * @return this.
     */
    public JSONObject put(String key, long value) {
        put(key, new Long(value));
        return this;
    }

    /**
     * Put a key/value pair in the JSONObject, where the value will be a
     * JSONObject which is produced from a Map.
     *
     * @param key A key string.
     * @param value A Map value.
     * @return this.
     */
    public JSONObject put(String key, Map value) {
        put(key, new JSONObject(value));
        return this;
    }

    /**
     * Put a key/value pair in the JSONObject. If the value is null, then the
     * key will be removed from the JSONObject if it is present.
     *
     * @param key A key string.
     * @param value An object which is the value. It should be of one of these
     * types: Boolean, Double, Integer, JSONArray, JSONObject, Long, String, or
     * the JSONObject.NULL object.
     * @return this.
     * @throws IllegalArgumentException if the value is non-finite number or if
     * the key is null.
     */
    public JSONObject put(String key, Object value) {
        if (key == null) {
            throw new IllegalArgumentException("Null key.");
        }

        if (value != null) {
            testValidity(value);
            this.map.put(key, value);
        } else {
            remove(key);
        }
        return this;
    }

    /**
     * Put a key/value pair in the JSONObject, but only if the key and the value
     * are both non-null, and only if there is not already a member with that
     * name.
     *
     * @param key
     * @param value
     * @return his.
     * @throws IllegalArgumentException if the key is a duplicate
     */
    public JSONObject putOnce(String key, Object value) {
        if (key != null && value != null) {
            if (opt(key) != null) {
                throw new IllegalArgumentException("Duplicate key \"" + key + "\"");
            }
            put(key, value);
        }
        return this;
    }

    /**
     * Put a key/value pair in the JSONObject, but only if the key and the value
     * are both non-null.
     *
     * @param key A key string.
     * @param value An object which is the value. It should be of one of these
     * types: Boolean, Double, Integer, JSONArray, JSONObject, Long, String, or
     * the JSONObject.NULL object.
     * @return this.
     * @throws IllegalArgumentException If the value is a non-finite number.
     */
    public JSONObject putOpt(String key, Object value) {
        if (key != null && value != null) {
            put(key, value);
        }
        return this;
    }

    /**
     * Produce a string in double quotes with backslash sequences in all the
     * right places. A backslash will be inserted within </, allowing JSON text
     * to be delivered in HTML. In JSON text, a string cannot contain a control
     * character or an unescaped quote or backslash.
     *

     *
     * @param string A String
     * @return A String correctly formatted for insertion in a JSON text.
     */
    public static String quote(String string) {
        if (string == null || string.length() == 0) {
            return "\"\"";
        }

        char b;
        char c = 0;
        int i;
        int len = string.length();
        StringBuffer sb = new StringBuffer(len + 4);
        String t;

        sb.append('"');
        for (i = 0; i < len; i += 1) {
            b = c;
            c = string.charAt(i);
            switch (c) {
            case '\\':
            case '"':
                sb.append('\\');
                sb.append(c);
                break;

            case '/':
                if (b == '<') {
                    sb.append('\\');
                }
                sb.append(c);
                break;

            case '\b':
                sb.append("\\b");
                break;

            case '\t':
                sb.append("\\t");
                break;

            case '\n':
                sb.append("\\n");
                break;

            case '\f':
                sb.append("\\f");
                break;

            case '\r':
                sb.append("\\r");
                break;

            default:
                if (c < ' ' || (c >= '\u0080' && c < '\u00a0') || (c >= '\u2000' && c < '\u2100')) {
                    t = "000" + Integer.toHexString(c);
                    sb.append("\\u" + t.substring(t.length() - 4));
                } else {
                    sb.append(c);
                }
            }
        }
        sb.append('"');
        return sb.toString();
    }

    /**
     * Remove a name and its value, if present.
     *
     * @param key The name to be removed.
     * @return The value that was associated with the name, or null if there was
     * no value.
     */
    public Object remove(String key) {
        return this.map.remove(key);
    }

    /**
     * Get an enumeration of the keys of the JSONObject. The keys will be sorted
     * alphabetically.
     *
     * @return An iterator of the keys.
     */
    public Iterator sortedKeys() {
        return new TreeSet(this.map.keySet()).iterator();
    }

    /**
     * Try to convert a string into a number, boolean, or null. If the string
     * can't be converted, return the string.
     *
     * @param s A String.
     * @return A simple JSON value.
     */
    static public Object stringToValue(String s) {
        if (s.equals("")) {
            return s;
        }
        if (s.equalsIgnoreCase("true")) {
            return Boolean.TRUE;
        }
        if (s.equalsIgnoreCase("false")) {
            return Boolean.FALSE;
        }
        if (s.equalsIgnoreCase("null")) {
            return JSONObject.NULL;
        }

        /*
         * If it might be a number, try converting it. We support the 0- and 0x-
         * conventions. If a number cannot be produced, then the value will just
         * be a string. Note that the 0-, 0x-, plus, and implied string
         * conventions are non-standard. A JSON parser is free to accept
         * non-JSON forms as long as it accepts all correct JSON forms.
         */

        char b = s.charAt(0);

        if ((b >= '0' && b <= '9') || b == '.' || b == '-' || b == '+') {
            if (b == '0') {
                if (s.length() > 2 && (s.charAt(1) == 'x' || s.charAt(1) == 'X')) {
                    try {
                        return new Integer(Integer.parseInt(s.substring(2), 16));
                    } catch (Exception e) {/*
                         * Ignore the error
                         */}
                } else {
                    try {
                        return new Integer(Integer.parseInt(s, 8));
                    } catch (Exception e) {/*
                         * Ignore the error
                         */}
                }
            }
            try {
                if (s.indexOf('.') > -1 || s.indexOf('e') > -1 || s.indexOf('E') > -1) {
                    return Double.valueOf(s);
                } else {
                    Long myLong = new Long(s);

                    if (myLong.longValue() == myLong.intValue()) {
                        return new Integer(myLong.intValue());
                    } else {
                        return myLong;
                    }
                }
            } catch (Exception f) {/*
                 * Ignore the error
                 */}
        }
        return s;
    }

    /**
     * Throw an exception if the object is an NaN or infinite number.
     *
     * @param o The object to test.
     * @throws IllegalArgumentException if o is a non-finite number.
     */
    static void testValidity(Object o) {
        if (o != null) {
            if (o instanceof Double) {
                if (((Double) o).isInfinite() || ((Double) o).isNaN()) {
                    throw new IllegalArgumentException("JSON does not allow non-finite numbers.");
                }
            } else if (o instanceof Float) {
                if (((Float) o).isInfinite() || ((Float) o).isNaN()) {
                    throw new IllegalArgumentException("JSON does not allow non-finite numbers.");
                }
            }
        }
    }

    /**
     * Produce a JSONArray containing the values of the members of this
     * JSONObject.
     *
     * @param names A JSONArray containing a list of key strings. This
     * determines the sequence of the values in the result.
     * @return A JSONArray of values.
     * @throws JSONException If any of the values are non-finite numbers.
     */
    public JSONArray toJSONArray(JSONArray names) throws JSONException {
        if (names == null || names.length() == 0) {
            return null;
        }
        JSONArray ja = new JSONArray();

        for (int i = 0; i < names.length(); i += 1) {
            ja.put(this.opt(names.getString(i)));
        }
        return ja;
    }

    /**
     * Make a JSON text of this JSONObject. For compactness, no whitespace is
     * added. If this would not result in a syntactically correct JSON text,
     * then null will be returned instead. <p> Warning: This method assumes that
     * the data structure is acyclical.
     *
     * @return a printable, displayable, portable, transmittable representation
     * of the object, beginning with
     * <code>{</code>&nbsp;<small>(left brace)</small> and ending with
     * <code>}</code>&nbsp;<small>(right brace)</small>.
     */
    public String toString() {
        try {
            Iterator keys = keys();
            StringBuffer sb = new StringBuffer("{");

            while (keys.hasNext()) {
                if (sb.length() > 1) {
                    sb.append(',');
                }
                Object o = keys.next();

                sb.append(quote(o.toString()));
                sb.append(':');
                sb.append(valueToString(this.map.get(o)));
            }
            sb.append('}');
            return sb.toString();
        } catch (Exception e) {
            return null;
        }
    }

    /**
     * Make a prettyprinted JSON text of this JSONObject. <p> Warning: This
     * method assumes that the data structure is acyclical.
     *
     * @param indentFactor The number of spaces to add to each level of
     * indentation.
     * @return a printable, displayable, portable, transmittable representation
     * of the object, beginning with
     * <code>{</code>&nbsp;<small>(left brace)</small> and ending with
     * <code>}</code>&nbsp;<small>(right brace)</small>.
     * @throws JSONException If the object contains an invalid number.
     */
    public String toString(int indentFactor) throws JSONException {
        return toString(indentFactor, 0);
    }

    /**
     * Make a prettyprinted JSON text of this JSONObject. <p> Warning: This
     * method assumes that the data structure is acyclical.
     *
     * @param indentFactor The number of spaces to add to each level of
     * indentation.
     * @param indent The indentation of the top level.
     * @return a printable, displayable, transmittable representation of the
     * object, beginning with
     * <code>{</code>&nbsp;<small>(left brace)</small> and ending with
     * <code>}</code>&nbsp;<small>(right brace)</small>.
     * @throws JSONException If the object contains an invalid number.
     */
    String toString(int indentFactor, int indent) throws JSONException {
        int j;
        int n = length();

        if (n == 0) {
            return "{}";
        }
        Iterator keys = sortedKeys();
        StringBuffer sb = new StringBuffer("{");
        int newindent = indent + indentFactor;
        Object o;

        if (n == 1) {
            o = keys.next();
            sb.append(quote(o.toString()));
            sb.append(": ");
            sb.append(valueToString(this.map.get(o), indentFactor, indent));
        } else {
            while (keys.hasNext()) {
                o = keys.next();
                if (sb.length() > 1) {
                    sb.append(",\n");
                } else {
                    sb.append('\n');
                }
                for (j = 0; j < newindent; j += 1) {
                    sb.append(' ');
                }
                sb.append(quote(o.toString()));
                sb.append(": ");
                sb.append(valueToString(this.map.get(o), indentFactor, newindent));
            }
            if (sb.length() > 1) {
                sb.append('\n');
                for (j = 0; j < indent; j += 1) {
                    sb.append(' ');
                }
            }
        }
        sb.append('}');
        return sb.toString();
    }

    /**
     * Make a JSON text of an Object value. If the object has an
     * value.toJSONString() method, then that method will be used to produce the
     * JSON text. The method is required to produce a strictly conforming text.
     * If the object does not contain a toJSONString method (which is the most
     * common case), then a text will be produced by other means. If the value
     * is an array or Collection, then a JSONArray will be made from it and its
     * toJSONString method will be called. If the value is a MAP, then a
     * JSONObject will be made from it and its toJSONString method will be
     * called. Otherwise, the value's toString method will be called, and the
     * result will be quoted.
     *
     * <p> Warning: This method assumes that the data structure is acyclical.
     *
     * @param value The value to be serialized.
     * @return a printable, displayable, transmittable representation of the
     * object, beginning with
     * <code>{</code>&nbsp;<small>(left brace)</small> and ending with
     * <code>}</code>&nbsp;<small>(right brace)</small>.
     * @throws JSONException If the value is or contains an invalid number.
     */
    static String valueToString(Object value) throws JSONException {
        if (value == null || value.equals(null)) {
            return "null";
        }
        if (value instanceof JSONString) {
            Object o;

            try {
                o = ((JSONString) value).toJSONString();
            } catch (Exception e) {
                throw new JSONException(e);
            }
            if (o instanceof String) {
                return (String) o;
            }
            throw new JSONException("Bad value from toJSONString: " + o);
        }
        if (value instanceof Number) {
            return numberToString((Number) value);
        }
        if (value instanceof Boolean || value instanceof JSONObject || value instanceof JSONArray) {
            return value.toString();
        }
        if (value instanceof Map) {
            return new JSONObject((Map) value).toString();
        }
        if (value instanceof Collection) {
            return new JSONArray((Collection) value).toString();
        }
        if (value.getClass().isArray()) {
            return new JSONArray(value).toString();
        }
        return quote(value.toString());
    }

    /**
     * Make a prettyprinted JSON text of an object value. <p> Warning: This
     * method assumes that the data structure is acyclical.
     *
     * @param value The value to be serialized.
     * @param indentFactor The number of spaces to add to each level of
     * indentation.
     * @param indent The indentation of the top level.
     * @return a printable, displayable, transmittable representation of the
     * object, beginning with
     * <code>{</code>&nbsp;<small>(left brace)</small> and ending with
     * <code>}</code>&nbsp;<small>(right brace)</small>.
     * @throws JSONException If the object contains an invalid number.
     */
    static String valueToString(Object value, int indentFactor, int indent)
        throws JSONException {
        if (value == null || value.equals(null)) {
            return "null";
        }
        try {
            if (value instanceof JSONString) {
                Object o = ((JSONString) value).toJSONString();

                if (o instanceof String) {
                    return (String) o;
                }
            }
        } catch (Exception e) {/*
             * forget about it
             */}
        if (value instanceof Number) {
            return numberToString((Number) value);
        }
        if (value instanceof Boolean) {
            return value.toString();
        }
        if (value instanceof JSONObject) {
            return ((JSONObject) value).toString(indentFactor, indent);
        }
        if (value instanceof JSONArray) {
            return ((JSONArray) value).toString(indentFactor, indent);
        }
        if (value instanceof Map) {
            return new JSONObject((Map) value).toString(indentFactor, indent);
        }
        if (value instanceof Collection) {
            return new JSONArray((Collection) value).toString(indentFactor, indent);
        }
        if (value.getClass().isArray()) {
            return new JSONArray(value).toString(indentFactor, indent);
        }
        return quote(value.toString());
    }

    /**
     * Write the contents of the JSONObject as JSON text to a writer. For
     * compactness, no whitespace is added. <p> Warning: This method assumes
     * that the data structure is acyclical.
     *
     * @return The writer.
     * @throws JSONException
     */
    public Writer write(Writer writer) throws JSONException {
        try {
            boolean b = false;
            Iterator keys = keys();

            writer.write('{');

            while (keys.hasNext()) {
                if (b) {
                    writer.write(',');
                }
                Object k = keys.next();

                writer.write(quote(k.toString()));
                writer.write(':');
                Object v = this.map.get(k);

                if (v instanceof JSONObject) {
                    ((JSONObject) v).write(writer);
                } else if (v instanceof JSONArray) {
                    ((JSONArray) v).write(writer);
                } else {
                    writer.write(valueToString(v));
                }
                b = true;
            }
            writer.write('}');
            return writer;
        } catch (IOException e) {
            throw new JSONException(e);
        }
    }
}
